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|
;------------------------------------------------------------------------------
; @file
; Sets the CR3 register for 64-bit paging
;
; Copyright (c) 2008 - 2013, Intel Corporation. All rights reserved.<BR>
; Copyright (c) 2017 - 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
BITS 32
; common for all levels
%define PAGE_PRESENT 0x01
%define PAGE_READ_WRITE 0x02
%define PAGE_USER_SUPERVISOR 0x04
%define PAGE_WRITE_THROUGH 0x08
%define PAGE_CACHE_DISABLE 0x010
%define PAGE_ACCESSED 0x020
%define PAGE_DIRTY 0x040
%define PAGE_GLOBAL 0x0100
; page table entries (level 1)
%define PAGE_PTE_PAT 0x080
; page directory entries (level 2+)
%define PAGE_PDE_LARGEPAGE 0x080
%define PAGE_PDE_PAT 0x01000
%define PAGE_4K_PDE_ATTR (PAGE_ACCESSED + \
PAGE_DIRTY + \
PAGE_READ_WRITE + \
PAGE_PRESENT)
%define PAGE_PDE_LARGEPAGE_ATTR (PAGE_PDE_LARGEPAGE + \
PAGE_ACCESSED + \
PAGE_DIRTY + \
PAGE_READ_WRITE + \
PAGE_PRESENT)
%define PAGE_PDE_DIRECTORY_ATTR (PAGE_ACCESSED + \
PAGE_READ_WRITE + \
PAGE_PRESENT)
%define TDX_BSP 1
%define TDX_AP 2
;
; For OVMF, build some initial page tables at
; PcdOvmfSecPageTablesBase - (PcdOvmfSecPageTablesBase + 0x6000).
;
; This range should match with PcdOvmfSecPageTablesSize which is
; declared in the FDF files.
;
; At the end of PEI, the pages tables will be rebuilt into a
; more permanent location by DxeIpl.
;
%macro ClearOvmfPageTables 0
mov ecx, 6 * 0x1000 / 4
xor eax, eax
.clearPageTablesMemoryLoop:
mov dword[ecx * 4 + PT_ADDR (0) - 4], eax
loop .clearPageTablesMemoryLoop
%endmacro
;
; Create page tables for 4-level paging
;
; Argument: upper 32 bits of the page table entries
;
%macro CreatePageTables4Level 1
;
; Top level Page Directory Pointers (1 * 512GB entry)
;
mov dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDE_DIRECTORY_ATTR
mov dword[PT_ADDR (4)], %1
;
; Next level Page Directory Pointers (4 * 1GB entries => 4GB)
;
mov dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDE_DIRECTORY_ATTR
mov dword[PT_ADDR (0x1004)], %1
mov dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDE_DIRECTORY_ATTR
mov dword[PT_ADDR (0x100C)], %1
mov dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDE_DIRECTORY_ATTR
mov dword[PT_ADDR (0x1014)], %1
mov dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDE_DIRECTORY_ATTR
mov dword[PT_ADDR (0x101C)], %1
;
; Page Table Entries (2048 * 2MB entries => 4GB)
;
mov ecx, 0x800
.pageTableEntriesLoop4Level:
mov eax, ecx
dec eax
shl eax, 21
add eax, PAGE_PDE_LARGEPAGE_ATTR
mov dword[ecx * 8 + PT_ADDR (0x2000 - 8)], eax
mov dword[(ecx * 8 + PT_ADDR (0x2000 - 8)) + 4], %1
loop .pageTableEntriesLoop4Level
%endmacro
;
; Modified: EAX, EBX, ECX, EDX
;
SetCr3ForPageTables64:
; Check the TDX features.
; If it is TDX APs, then jump to SetCr3 directly.
; In TD guest the initialization is done by BSP, including building
; the page tables. APs will spin on until byte[TDX_WORK_AREA_PGTBL_READY]
; is set.
OneTimeCall CheckTdxFeaturesBeforeBuildPagetables
cmp eax, TDX_BSP
je ClearOvmfPageTables
cmp eax, TDX_AP
je SetCr3
; Check whether the SEV is active and populate the SevEsWorkArea
OneTimeCall CheckSevFeatures
; If SEV is enabled, the C-bit position is always above 31.
; The mask will be saved in the EDX and applied during the
; the page table build below.
OneTimeCall GetSevCBitMaskAbove31
ClearOvmfPageTables:
ClearOvmfPageTables
CreatePageTables4Level edx
; Clear the C-bit from the GHCB page if the SEV-ES is enabled.
OneTimeCall SevClearPageEncMaskForGhcbPage
; TDX will do some PostBuildPages task, such as setting
; byte[TDX_WORK_AREA_PGTBL_READY].
OneTimeCall TdxPostBuildPageTables
SetCr3:
;
; Set CR3 now that the paging structures are available
;
mov eax, PT_ADDR (0)
mov cr3, eax
OneTimeCallRet SetCr3ForPageTables64
|
